Skip to main content
Stesso
Project

Install Waterproofing Membrane — Install New Tile

Intermediate

Part of project

How to Replace a Shower Valve Through a Tiled Wall · Step 9 of 11

Helpful?

In this video

Take a pre-cut sheet of the waterproofing membrane and carefully place it onto the wet mortar, aligning one edge with your laser line. Starting from the center, use the flat side of your trowel to firmly press the membrane into the mortar. Work your way out towards the edges, applying pressure at a 45-degree angle to embed the fleece fabric fully and squeeze out any air bubbles. Ensure the membrane is pressed firmly into any inside corners.

Goal: Embed the membrane into the mortar

  • Removing all air bubbles is crucial, as they create voids and prevent a proper bond, compromising the waterproof seal.
  • Do not use a sharp edge of the trowel on the membrane, as it can tear. Use the flat, smooth side.

Used in this video

  • Trowel (Flat Side) (brand: Schluter, Tool Type: Hand Tools, Power Source: Manual) — Embedding the membrane into the mortar and removing air bubbles.
12.7K views3115 minutes
This Old House

2.2M subscribers

View Channel

FAQs

What specialized tools are essential for safely replacing the shower valve and repairing the tiled wall?

You'll need a tubing cutter (like the RIDGID 104) to precisely cut existing pipes and a high-intensity propane torch (Flame King FK4500CGA) with lead-free solder (Oatey Safe Flo) for connections. For tile work, a QEP grout float for finishing and a pry bar (Stanley 55-515K) for tile removal are helpful. Don't forget safety glasses and gloves.

What critical safety steps should I follow, especially when dealing with water and soldering in a bathroom?

Always shut off your home's main water supply before beginning to prevent flooding. When soldering, ensure excellent ventilation by opening windows or using a fan, and have a fire extinguisher or a bucket of water readily available. Wear appropriate personal protective equipment like safety glasses and heavy-duty gloves.

How long does this project typically take, what's the estimated cost, and is it truly intermediate difficulty for a DIYer?

This project is rated intermediate and can realistically take 1-2 full days, especially allowing for proper drying and cure times for grout and caulk. Costs can range from $100-$300+ for a new valve, plumbing parts, and tile repair materials, not including tools you may need to purchase. It requires patience and attention to detail.

What are the most common mistakes DIYers make during a shower valve replacement, and how can I avoid them?

A common mistake is not fully shutting off water or not performing thorough leak tests, leading to hidden leaks. Another is improper soldering, which can also cause future failures; practice on scrap pipes first. Ensure the new valve is properly aligned and secured before making final connections, and test rigorously.

Transcript
Hide

applied in advance. So now we're actually going to start installing the membrane itself. So we've got it cut to length already. So what we want to do is use the ceiling as a guide to start and our laser level line. It's more important to pay attention to the laser that it is the ceiling because the laser will be straight and level. The ceiling might not be. Always follow the laser. Laser retrust. Now that we've got our membrane sort of loosely set into place, go back to our trowel and start using our trowel as sort of a screed to really force that inset to get a full coverage on the back of the membrane. Any rid of any air bubbles that might exist, air bubbles will create a loss of bond between the tiles and the walls. We really want to firmly press the trowel into the corner and create a nice crisp inside corner but we don't want to tear the membrane so just gently. As we make our way down into this corner, we need to kind of fold this guy over top of

Auto-generated transcript. May contain errors.